1. Field of the Invention
The present invention relates to breast reconstruction, more particularly, to techniques for preserving the breast skin envelope for breast reconstruction.
2. Description of Related Art
For breast cancer patients who undergo mastectomies and desire breast reconstruction, reconstructive surgery generally occurs soon after the mastectomy, if not immediately after the mastectomy, to permit the best aesthetic outcomes. For patients with early-stage breast cancer, either stage 1 or stage 2 breast cancer, immediate reconstruction is feasible because these patients do not generally require post-operative radiation therapy. However, if the need for post-mastectomy treatment arises after the breast is reconstructed, the patient may be at an increased risk for complications, such as adverse aesthetic results and inhomogeneous radiation delivery. For example, as noted in many trials, survival advantages with post-mastectomy treatment occur when the internal mammary nodes are included within the radiation fields. To treat these internal mammary nodes while minimizing the dose to the heart and lungs, a separate electron beam on the medial chest wall is required to match the laterally placed opposed tangent fields. However, the sloping contour of a reconstructed breast leads to an imprecise geometric matching of the fields, and thus results in either exclusion of treatment to the internal mammary nodes and/or increased radiation of normal tissues. Additionally, the radiation may increase the chances of capsular contracture with an implant-based reconstruction, which can distort the appearance of the reconstructed breast and cause chronic chest wall pain and tightness among other issues. Autologous tissue can also be adversely affected by radiation treatments resulting in the necrosis of tissue that can result in complications and asymmetry with the constructed breast. Any surgical revisions to a radiated breast reconstruction can be unpredictable and cause multiple complications, as well as require multiple steps.
In recent trials, such as Danish and Vancouver Trials, results show that for patients with early-stage breast cancer, post-mastectomy radiation therapy in addition to chemotherapy reduces the rate of locoregional recurrences and increases survival rates. Unfortunately, the need for post-mastectomy radiation therapy cannot be reliably determined at the time of a mastectomy. Pathology analysis of the mastectomy specimen and nodal tissue on permanent sections removed during a mastectomy is performed before a decision of whether a patient needs post-operative treatments can be made, with results taking upwards of a week to return. This delay may cause reconstruction to be pushed back, affecting aesthetic outcomes for reconstruction. For example, for standard delayed reconstruction, if the breast skin is not completely removed, any remaining skin may be undesirable because the skin malleability or elasticity deteriorates during the waiting period and/or during any post-operative therapy. Any subsequent reconstruction will be less than desirable, causing physical, emotional, and physiological distress to the patient.
Currently, different devices are being used to prepare the breast area for a permanent implant. One example is a tissue expander, which typically includes a bladder or envelope that will hold a liquid such as saline. The tissue expander can be used to stretch any skin remaining from the mastectomy to a larger dimension, particularly to a dimension that can accommodate the breast implant. In order to stretch the skin, after the mastectomy, the tissue expander is implanted under tissue, such as under the muscles below a surgically removed breast. Prior to the placement of the permanent breast implant, a small amount of saline is added to the envelope periodically until a desired size is reached. Typically, by adding the liquid slowly over a period of weeks or months, the covering tissue is allowed to expand to accommodate the liquid. Alternatively, the bladder may be completely filled intraoperatively
One problem with using tissue expanders after a mastectomy is the stretching of the tissue and/or the skin. Due to the removal of most tissue and/or skin in the breast area during the mastectomy, any remaining tissue and/or the skin can be stretched thin enough that damages such as tearing or protrusion of the tissue expander and/or an implant through the skin can occur. The surface, therefore, becomes too delicate and hard to work with during reconstruction.
If pathology results show that a patient requires post-mastectomy radiation therapy and/or chemotherapy, the tissue expanders may need to be removed to optimize treatment. For example, among other issues, if the inflated tissue expander remains on the chest wall, the tissue expander may deflect radiation beams, causing an inhomogeneous radiation field that exposes areas not needing therapy or not treating the regions that require treatment. Also, the tissue expander may be damaged due to the radiation beam, and thus may leak or otherwise lead to undesirable results. Subsequently, the tissue expander may need to be removed in order to proceed with post-mastectomy therapy (i.e., radiation therapy).
Alternatively, if a patient requires post-mastectomy radiation therapy, the liquid in the tissue expander may be removed prior to the treatment. This method cuts down the recovery time for the patient and may avoid delays in the start of post-mastectomy therapies. Generally, to deflate the tissue expander, a needle is inserted into a metal port integrated into the envelope of the tissue expander to draw out the liquid. However, there are complications caused by the metal port used to fill and drain the envelope. If a patient requires post-mastectomy radiation therapy and the tissue expander remains in the patient, the metal port can deflect the radiation beam, resulting in an inhomogeneous radiation field. Areas not needing radiation therapy may be exposed and can cause more harm to the patient, and areas needing treatment may not receive the radiation
Another problem associated with current tissue expanders is when they are deflated, the bladder of the tissue expander curls in at the edges, creating a cupped profile. These cupped edges can deflect radiation beams. These edges may also cause pressure to the overlying skin and cause the skin to become irritated and/or cause the tissue expander to become exposed or protrude through the skin. Further, the backward pressure created by the expansion can push against the chest wall, creating a concave deformity on the surface on the chest wall. This can result in discomfort to the patient, including, but not limited to, pain and breathing problems. Upon reconstruction, the concave nature of the chest wall can create aesthetic problems, e.g., requiring more tissue to fill the space. This problem may create an unnatural breast shape and asymmetry with the contralateral breast.
Other problems associated with current tissue expanders include the deficiencies of removing fluids that collect at the expander after removal of the surgical drain, such as, for example, seroma fluids collecting at or around the breast region. Generally, patients would be required to undergo needle drainage and the use of an external catheter. The insertion of the needle may require radiographic imaging to avoid inadvertent puncturing of the expander. Additionally, the long-term use of the drainage catheter may cause a great risk of infection to the patient. As such, the inadvertent collection of peri-expander fluid in the breast and axillary area can be costly, cause significant complications, and can be inconvenient for the patient.
Any shortcoming mentioned above is not intended to be exhaustive, but rather is among many that tends to impair the effectiveness of previously known techniques for breast reconstruction; however, shortcomings mentioned here are sufficient to demonstrate that the methodologies appearing in the art have not been satisfactory and that a significant need exists for the techniques described and claimed in this disclosure.